PbI<sub>6</sub> Octahedra Stabilization Strategy Based on π‐π Stacking Small Molecule Toward Highly Efficient and Stable Perovskite Solar Cells
Xianzhao Wang, Dachang Liu, Ruichen Liu, Xiaofan Du, Bingqian Zhang, Xiuhong Sun, Chen Chen, Zhipeng Li, Qiangqiang Zhao, Zhipeng Shao, Xiao Wang, Guanglei Cui, Shuping Pang
Abstract
Abstract The unavoidable iodine loss in the perovskite layer is closely related to carrier non‐radiative and device degradation. During the post‐annealing process, the fragile PbI bond is easy to break, leading to the formation of iodine vacancies and inducing stress‐driven structure collapse. Herein, a PbI 6 octahedra stabilization strategy via building robust grain boundary modification networks is developed. The introduction of conjugated structure into amides can significantly enhance their anchoring ability with PbI units, while the π–π stacking effect of benzamide enables a passivation network with polymer‐like effect. This is well evidenced by the excellent properties in eliminated iodine loss and stabilized perovskite lattice. Therefore, benzamide modification not only transform the perovskite films from n‐type to p‐type by suppressing the iodine vacancy‐doping effect, but also reduces defect density, ultimately bringing the perovskite layer longer carrier diffusion length and better charge injection efficiency. Finally, the benzamide modified devices realize both high power conversion efficiency of 24.78% and excellent operating stability. Of particular note, the module efficiency with 14 cm 2 active area is over 21%.